Traditional eye medication and pterygium occurrence in Limpopo Province.

Background: The relative importance of environmental and hereditary factors in the occurrence of pterygium in African blacks has not been reported.

Aim: To investigate the relative significance of factors associated with pterygium occurrence.

Methods: This was a prospective case-controlled study where 150 pterygium patients and 150 controls participated. Interviews were conducted, eyes examined and multivariate analysis done. The families of 51 pterygium cases and 50 controls were examined for presence of pterygium.

Results: Of 150 cases and 150 controls, 79 (52.6%) and 60 (40%) used traditional eye drops (odds ratio (OR) 2.03; p=0.009. Ten cases (6.6%) and 26 controls (17.3%) had unstable tear film (OR 0.30; p=0.007. Forty-six cases (30.6%) and 15 controls (10%) reported a positive family history (OR 3.93; p<0.001). Groups of 3 - 5 pterygium cases in a household occurred in 36 of 51 pterygium families (70.5%) v. 1 of 50 controls (2%).

Conclusions: Pterygium occurrence was associated with the use of traditional eye drops, a positive family history and having groups of diagnosed pterygium-affected relatives. However, unstable tear film seemed protective against pterygium occurrence.